Today Best Buy announced Music Cloud, a new cloud storage and music streaming solution for computers and smartphones.

If you've been reading our coverage of Amazon Cloud Player and Google Music Beta, Best Buy's offering aims to do the same thing: store your music online, then beam it down to computers and smartphones on the go.

Music Cloud is free to use for listening from a computer, but will cost $4.00/month to use for mobile streaming on a smartphone.

Interestingly enough, Music Cloud requires that you have an iTunes Library for it to mine for tracks to upload to its service.

Best Buy also owns Napster, which has its own streaming music service and app. The only difference is that Napster, like Rhapsody, is a subscription product offering unlimited listening to Napster's entire music library for a set price per month.

We've used Napster's music store before, and it's a pretty horrible experience. Hopefully Music Cloud will fare better, because Apple devices are noticeable short on apps that stream music you already own from the cloud.

Music Cloud will offer mobile apps for iPhone, Android, and Blackberry, although the iPhone app doesn't have "premium services."

All the details regarding what "premium services" means, how much storage you'll have, and how it all works is still unclear.